The invention relates to a vacuum producing device for operation on the so-called ejector principle and adapted to serve to produce vacuum in the space defined by a vacuum plate or suction cup for materials handling and to systematically cut such vacuum when required using a gage pressure pulse.
A vacuum producing device disclosed in the German utility model 29,903,330 comprises a housing with inlet and suction connections arranged on oppositely placed inlet and suction sides, a suction nozzle means being accommodated in the housing between the connections and being aligned in the transverse direction, such suction connection nozzle being able to produce a suction effect at the suction connection. During suction operation a pressure plenum is charged, which is able to produce a gage pressure pulse for introducing air into the suction space, a valve arranged in an extension of the suction nozzle means being employed for control of the gage pressure pulse, such valve being designed as a component of an air economizing means. Said known device is relatively bulky.
One object of the present invention is to provide a vacuum producing device, which may be manufactured with substantially smaller dimensions in order to favor installation in situations where space is at a premium.
A vacuum producing device disclosed in the German utility model 29,903,330 comprises a housing with inlet and suction connections arranged on oppositely placed inlet and suction sides, a suction nozzle means being accommodated in the housing between the connections and being aligned in the transverse direction, such suction nozzle being able to produce a suction effect at the suction connection. During suction operation a pressure plenum is charged, which is able to produce a gage pressure pulse for introducing air into the suction space, a valve arranged in an extension of the suction nozzle means being employed for control of the gage pressure pulse, such valve being designed as a component of an air economizing means.
Said known device is relatively bulky. Accordingly one object of the present invention is to provide a vacuum producing device, which may be manufactured with substantially smaller dimensions in order to favor installation in situations where space is at a premium.
In order to attain this object a vacuum producing device is provided comprising a housing, which on an inlet side has an inlet connection for supplying a fluid pressure medium and, on a suction side opposite to the inlet side, a suction connection which is connected or fluid pressure medium and, on a suction side opposite to the inlet side, a suction connection which is connected or able to be connected with the suction space, an elongated suction nozzle means arranged in the housing and extending in the same direction as an imaginary linear connecting line running between the inlet connection and the suction connection, an inflow opening, which is aligned like the inlet connection, of such suction nozzle means being connected with the inlet connection and a suction opening of said suction nozzle means being connected with the suction connection, and the outflow opening of said suction nozzle means being connected with an outlet, such outlet being located on an outlet side, of said housing, aligned athwart the imaginary connecting line and also athwart the longitudinal extent of the suction nozzle means, and an elongated gage pressure pulse means arranged in the housing alongside and adjacent to the suction nozzle means with the same alignment as same, such gage pressure means serving for producing a fluid gage pressure pulse for the suction space, such gage pressure means having a switching valve combined with a pressure plenum, said valve having a first valve opening connected with the inlet connection and a second valve opening connected with the suction side, said valve having a valve member being arranged to be so operated in a manner dependent on a pressure differential applied to it that the pressure plenum is connected either with the first or with the second valve opening for the passage of fluid.
It is in this manner that a vacuum producing device can be provided possessing an extremely slim, compact configuration. The inlet connection and the suction connection are arranged opposite to one another on mutually opposite sides of the housing, the suction nozzle means and the gage pressure pulse means being arranged longitudinally alongside each other in the housing with the same alignment as an imaginary connecting line joining the inlet connection and the suction connection. Since the correspondingly placed gage pressure pulse means also contains the pressure plenum, it is possible to do without external pressure plenum means and all component are collected together in a minimum space. In connection with the generally linear design of the vacuum producing device there is as a result a high degree of efficiency as well with a small number of points at which flow is redirected. All in all the vacuum producing device is characterized by a rapid pressure decay time if necessary in the suction space, since the gage pressure being established in the pressure plenum can cause an automatic switching of the switching valve when there is an interruption in the supply of pressure medium owing to the change, resulting therefrom, of the pressure values, so that the pressure medium so far stored may flow to the suction connection and cause an abrupt build up of gage pressure in the suction space. Such gage pressure pulse can in cooperation with materials handling equipment represent a disengagement pulse, which results in a more or less sudden release of an object which so far has been held.
Further advantageous developments of the invention are defined in the dependent claims.
It is convenient for the inlet connection and the suction connection to be so placed on the inlet and, respectively, suction side that their longitudinal axes coincide and lie on the said imaginary connecting line.
The space saving arrangement alongside each other of a plurality of vacuum producing devices is favored, if the housing has an elongated configuration, the inlet side and the suction side being constituted by the two end sides of the housing and the outlet side being constituted by a longitudinal side, which is aligned in the sideways direction, of the housing. It is preferred for the imaginary connecting line to coincide with the longitudinal axis of the housing or to be at least parallel to it.
It is furthermore advantageous, if the suction nozzle means and the gage pressure pulse means are arranged alongside each other so that their longitudinal sides are parallel to each other. Their overall lengths will then conveniently be at least substantially the same and they will be more particularly at the same level as related to the longitudinal direction of the housing.
The installation of the suction nozzle means and of the gage pressure pulse means is particularly simple, if the respective components are accommodated in two sockets of the housing, said sockets being arranged longitudinally alongside one another. It is possible for one or both means to be in the form of cartridge-like components, which preferably may be inserted through a terminal opening into the respective socket in the housing.
For connection with fluid ducts leading to other equipment the inlet connection or the outlet is more particularly provided with plug connection means rendering possible the connection of fluid ducts for assembly simply by inserting plugs.
Dependent on the particular application different periods may be required for blowing air into a suction space at the desired gage pressure. In order to be able to influence such blow-in period, an adjustable choke may be provided on the connection between the second valve opening of the switching valve and the suction connection, such choke being able to be set as regards the choke intensity produced.
In keeping with a preferred, compact and appropriate form of the gage pressure pulse means the moving valve member is located between the mutually opposite valve openings, the two valve openings being constituted by the bore of a tube body and being connected by way of the tube body with the suction connection and the pressure plenum being formed by an annular space surrounding the tube body. The result is then an extremely space saving and compact combination between the switching valve and the pressure plenum.
In this connection it is particularly advantageous to have a bell- or pot-like configuration of the valve member having an uninterrupted floor and a surrounding side wall forming an elastically flexible sealing lip, the floor serving as a closure member for the second valve opening and the sealing lip being biased toward the inner face of a transition space connecting the first valve opening with the pressure plenum and extending toward the pressure plenum so that it is able to be bent over inward by the pressure medium flowing in by way of the first valve opening and subject to the operational pressure and filling of the pressure plenum may take place by flow past the valve member.